Common Brittlestar

Ophiothrix fragilis

What do they look like?

The brittlestar’s bodies, known as discs, are slightly pentagonal in shape. Their five long arms are banded in colouration and can be five times the disc’s diameter. They also appear hairy due to their many spines. However, these limbs are easily broken off when the animal feels threatened (hence its name) so you might find that some are missing. It is difficult to distinguish the common brittlestar from other brittlestar species, as the common brittlestar can be many different colours ranging from brown to yellow, red or even purple.

Where can I find them in Scotland?

The common brittlestar is found all around the UK’s coasts, but in Scotland they are most common in the west. They prefer hard substrates and can be found in rockpools and on the lower shore, often underneath seaweed or rocks or tucked into crevices. They can also be found on the seabed to a depth of 85 metres, often in large groups.

Fun Fact
Common brittlestars typically feed on phytoplankton. They achieve this by waving their five flexible arms around, trapping the tiny floating particles in the sticky mucous strands attached to their tube feet. They have been found to form groups of as many as 2000 individuals per square metre where food is abundant.
2mm - 2cm
Disc Diameter
5-10 years
Conservation Status
A close-up of a common brittlestar upon coarse sand
© Andrew Grieveson